2 related(?) questions: How to scale or extrude multiple selections together?
In Blender, you can change the behavior of these operations like extrude and scale to suite your needs by setting the Pivot Point. The select menu is located in the bottom bar in 3D view.



In your case, you need to extrude or scale selected loops / faces individualy, so you need to select the Pivot Point to Individual Origins:



You can also use the shortcut Ctrl. for that.
For switching back to Bounding Box Center, use ,

The result - scale:


Extrude